This set of Manufacturing Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Arc Welding”.
1. Amount of time during which the transformer will be used for welding under normal loading condition is known as?
a) Hold time
b) Off time
c) Weld time
d) Duty cycle
View Answer
Explanation: Amount of time during which the transformer will be used for welding under normal loading condition is known as the duty cycle.
2. Amount of voltage required to generate the arc under no load condition is called?
a) Open circuit voltage
b) Closed circuit voltage
c) Short circuit voltage
d) Arc voltage
View Answer
Explanation: Amount of current required to generate the arc under no load condition is called short circuit current (SCC).
3. Amount of current required to generate the arc under no load condition is called?
a) Open circuit current
b) Closed circuit current
c) Short circuit current
d) Arc current
View Answer
Explanation: Amount of current required to generate the arc under no load condition is called short circuit current. It is represented by SCC.
4. If the open circuit voltage is 60 volt and the short circuit current is 20 amperes. Then determine the voltage required for welding if the current required during welding is 10 amperes?
a) 30 V
b) 60 V
c) 20 V
d) 40 V
View Answer
Explanation: Voltage = OCV – (\(\frac{I}{SCC}\))×OCV, where “OCV” is open circuit voltage, “SCC” is short circuit voltage and “I” represents the current in amperes.
5. How does the arc voltage V depends upon the length of arc L?
a) V = f(L)
b) V = 1/f(L)
c) V = f(L2)
d) V = f(√L)
View Answer
Explanation: V= A+BL, where ‘V’ is the arc voltage and ‘L’ is the length of arc in cm, A & B are constants.
6. What is the function of flux in submerged arc welding?
a) To completely cover the welded zone
b) To prevent oxidation of joint
c) To prevent spattering of molten metal
d) To prevent sticking of molten metal
View Answer
Explanation: Flux is used to completely cover the welded zone. It prevents oxidation of weld joint and spattering of molten metal.
7. In which of the following gas welding process a non-consumable electrode is used?
a) Submerged arc welding
b) Tungsten inert gas welding
c) Stud welding
d) Gas metal arc welding
View Answer
Explanation: In tungsten inert gas welding process a non-consumable electrode is used, which is made of tungsten.
8. What is the only difference between Plasma arc welding and TIG welding?
a) Flux is not used
b) Construction of torch is different
c) Gas is not used
d) Tungsten electrode is not used
View Answer
Explanation: Construction of the torch is the only difference between Plasma arc welding and TIG welding. Both the TIG and PAW are uses tungsten electrodes.
9. In plasma arc welding the gas is?
a) Ionized
b) Heated
c) Magnetized
d) Vaporized
View Answer
Explanation: In plasma arc welding the gas is ionized. Electrode used is made of tungsten and filler metal is used addition to it.
10. If the heat transfer efficiency is 0.5 and the melting efficiency is 0.6, then the overall efficiency will be?
a) 0.83
b) 0.03
c) 0.30
d) 0.12
View Answer
Explanation: ηtotal = ηmelting * ηheat transfer, where η denotes efficiency. There are two types of efficiencies, one is melting efficiency and another is heat transfer efficiency.
11. The deflection of the arc in arc blow is by?
a) Electric field
b) Magnetic field
c) Combination of both
d) Hydrostatic field
View Answer
Explanation: The deflection of the arc in arc blow is by a magnetic field. Electric field, hydrostatic field does not affect the deflection of the arc.
12. If the total efficiency is 0.35 in arc welding. Then what is the welding speed in mm/sec if the cross-sectional area is 5mm2, welding power is 2 kW and the heat required in melting the metal is 100 J/mm3.
a) 1.4
b) 14
c) 1400
d) 140
View Answer
Explanation: N = (P×total efficiency)/(Q×A), where P represents power, q represents heat transfer, and A represents the cross-sectional area.
13. Which of the following gas welding process uses constant voltage?
a) Submerged arc welding
b) Tungsten inert gas welding
c) Stud welding
d) Gas metal arc welding
View Answer
Explanation: Gas metal arc welding uses constant voltage. Tungsten inert gas welding does not use constant circuit voltage.
14. Which of the following inert gas is used with DC power supply only?
a) Argon
b) Helium
c) CO2
d) Nitrogen
View Answer
Explanation: Co2 is used only in DC power supply. It cannot be used in AC power supply. Argon and helium can be used with AC supply.
15. In order to prevent oxidation and retain molten metal in stud welding which of the following is used?
a) Ceramic rings
b) Metal rings
c) Non-metal rings
d) Flux
View Answer
Explanation: In order to prevent oxidation and retain molten metal in stud welding ceramic rings are used.
Sanfoundry Global Education & Learning Series – Manufacturing Engineering.
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